In recent years, there have been increasingly widespread digital devices (camcorder, digital still camera, camera-equipped mobile phone, and so on) capable of recording and storing an image (video) taken and a sound (audio) as digital data in an optical disk such as a DVD and Blu-ray (registered trademark), magnetic disk such as a hard disk drive, and recording medium such as a semiconductor memory.
Further, as digital broadcasting and hi-vision home televisions have been introduced, an aspect ratio of image to be taken has been shifted from 4:3 to 16:9. Further, regarding a digital still camera, a digital still camera which has the aspect ratio of not only 4:3 but also 16:9 and is capable of taking images in hi-vision size, have appeared on the market.
When such an image is displayed on a home television designed for hi-vision digital broadcasting, an image with aspect ratio of 16:9 is displayed on full screen.
Incidentally, for example when an image is taken with a digital camera, there are several types of usage of the digital camera, including a usage type where the camera is held horizontally (in a normal orientation), a usage type where the camera is held with its right side turned upward (in a 90-degree rotated orientation), and a usage type where the camera is held with its left side turned upward (in a 270-degree rotated orientation). In particular, in the case of taking an image with the camera vertically held, a built-in sensor of the camera detects that the user has taken a picture while vertically holding the camera, and records, as orientation information, a value corresponding to 90 degrees or 270 degrees showing the inclination of the camera to a file header of a JPEG file to be recorded as taken picture data.
Subsequently, when reproducing the JPEG file on the digital camera, the orientation information in the file header of the recorded JPEG file is referred to, and a picture is displayed in an orientation corresponding to an inclination shown by the orientation information. For example, when the value of 90 degrees is recorded in the orientation information, as shown in FIG. 6A, a reproduced image 400 having the aspect ratio of 16:9 is displayed in the vertical orientation on a display screen 150 having the aspect ratio of 16:9 on a LCD (liquid crystal display) monitor mounted on the camera body. Similar display applies to a case where an analog signal output of the digital camera is connected to a home television. On the other hand, when the value of 0 degrees is recorded in the orientation information, as shown in FIG. 6B, the reproduced image 400 is displayed in the horizontal orientation on a LCD monitor.
It is noted that Patent Document 1 discloses, as a related technique, an example method of displaying a still image having an aspect ratio of 4:3 on the monitor screen of the aspect ratio of 16:9.    Patent Document 1: JP 2005-173471 A.